We have been wrongly advised to avoid saturated fat and cholesterol, despite no evidence of harm.

Here are the top 9 biggest lies, myths and misconceptions about dietary fat and cholesterol.

1. A Low-Fat, High-Carb Diet is The Optimal Human Diet

Back in 60s and 70s, many prominent scientists believed that saturated fat was the main cause of heart disease, by raising the "bad" cholesterol in the blood.

This idea was the cornerstone of the low-fat diet. Because of a few bad studies and misguided political decisions, this diet was recommended to all Americans in the year 1977 (1).

However, there wasn't a single study on this diet at the time. The American public became participants in the largest uncontrolled experiment in history.

This experiment didn't turn out very well and we are still suffering the consequences. This graph shows how the obesity epidemic started at almost the exact same time the low-fat guidelines came out (2):

The diabetes epidemic followed soon after. Of course, a graph like this doesn't prove anything. Correlation does not equal causation.

But it seems plausible that the low-fat recommendations made things worse because people started eating less of healthy foods like meat, butter and eggs, while eating more processed foods high in sugar and refined carbohydrates.

Even though there was little evidence at the time, the low-fat diet has actually been thoroughly studied in the past few years and decades.

It was put to the test in the biggest controlled trial in nutrition history, the Women's Health Initiative. In this study, 48,835 postmenopausal women were split into two groups. One group ate a low-fat diet (with the whole grains and all that) while the other group continued to eat "normally."